Hey guys... so this is an odd one.

When the windshield wipers are on any setting other than high speed, the longest wiper will occasionally catch on the bottom of the shortest one and cause the entire arm to pop up and slam back down into the glass. I've checked and it appears that the wipers are the correct specs, but for the life of me I can't figure out why the timing is wrong or some such thing. Ideas?

Firstly - I am assuming LHD and RHD cars are a mirror image re the wipers.

On my (RHD), the longest blade should be on the driver's side. Check that is correct. Also check you have the correct arms. The driver's side has a downwards bend in it, putting the parked blade almost horizontal. The passenger side is straight, putting the parked blade at about 10 degrees up towards the side of the car. If that is all ok, then either an arm is bent or one (or both) of the arms are misaligned. I believe they are on splined drives which would provide limited adjustment (in 10-15 degree steps). If none of the above, then I guess you have some misaligned or worn linkage below the scuttle.

Bob 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

Everything looked copacetic, but when this damnable rain lets up, I'll give it another look and see if everything matches your description. Thanks!

'Copacetic', meaning something is in excellent order or satisfactory, is an obscure American expression with many stories about where it comes from. We have some obscure expressions too - but I cannot print them!  10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

Ha! Oh, no... please do! An ever-expanding vernacular of international off-color sayings is something every man should pursue!

Update: Took my LR in for some warranty work and they took a cursory glace at the wipers. "There's a bolt that sometimes works a little free on the driver's side that can allow this to happen." My assumption is one of the mount points for the wiper motors, but I'll know for sure when they complete the work (wipers, dead satellite radio, dead AM radio, wobbly driver's seat, and dead FOB on delivery).